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Wang C, Wang H, Tian Q, Zong J, Xie X, Chen W, Zhang Y, Wang K, Qiu X, Wang L, Li F, Zhang H, Zhang Y. Suppression of Intervalley Coupling in Graphene via Potassium Doping. J Phys Chem Lett 2022; 13:9396-9403. [PMID: 36190902 DOI: 10.1021/acs.jpclett.2c02657] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The quantum interference patterns induced by impurities in graphene can form the (√3 × √3)R30° superlattice with intervalley scattering. This superlattice can lead to the folded Dirac cone at the center of Brillouin zone by coupling two non-equivalent valleys. Using angle-resolved photoemission spectroscopy (ARPES), we report the observation of suppression of the folded Dirac cone in mono- and bilayer graphene upon potassium doping. The intervalley coupling with chiral symmetry broken can persist upon a light potassium-doped level but be ruined at the heavily doped level. Meanwhile, the folded Dirac cone can be suppressed by the renormalization of the Dirac band with potassium doping. Our results demonstrate that the suppression of the intervalley scattering pattern by potassium doping could pave the way toward the realization of novel chiraltronic devices in superlattice graphene.
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Affiliation(s)
- Can Wang
- National Laboratory of Solid State Microstructure, School of Physics, Nanjing University, Nanjing, Jiangsu 210093, People's Republic of China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, Jiangsu 210093, People's Republic of China
| | - Huaiqiang Wang
- National Laboratory of Solid State Microstructure, School of Physics, Nanjing University, Nanjing, Jiangsu 210093, People's Republic of China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, Jiangsu 210093, People's Republic of China
| | - Qichao Tian
- National Laboratory of Solid State Microstructure, School of Physics, Nanjing University, Nanjing, Jiangsu 210093, People's Republic of China
| | - Junyu Zong
- National Laboratory of Solid State Microstructure, School of Physics, Nanjing University, Nanjing, Jiangsu 210093, People's Republic of China
| | - Xuedong Xie
- National Laboratory of Solid State Microstructure, School of Physics, Nanjing University, Nanjing, Jiangsu 210093, People's Republic of China
| | - Wang Chen
- National Laboratory of Solid State Microstructure, School of Physics, Nanjing University, Nanjing, Jiangsu 210093, People's Republic of China
| | - Yongheng Zhang
- National Laboratory of Solid State Microstructure, School of Physics, Nanjing University, Nanjing, Jiangsu 210093, People's Republic of China
| | - Kaili Wang
- National Laboratory of Solid State Microstructure, School of Physics, Nanjing University, Nanjing, Jiangsu 210093, People's Republic of China
| | - Xiaodong Qiu
- National Laboratory of Solid State Microstructure, School of Physics, Nanjing University, Nanjing, Jiangsu 210093, People's Republic of China
| | - Li Wang
- Vacuum Interconnected Nanotech Workstation (Nano-X), Suzhou Institute of Nano-Tech and Nano-Bionics (SINANO), Chinese Academy of Sciences (CAS), Suzhou, Jiangsu 215123, People's Republic of China
| | - Fangsen Li
- Vacuum Interconnected Nanotech Workstation (Nano-X), Suzhou Institute of Nano-Tech and Nano-Bionics (SINANO), Chinese Academy of Sciences (CAS), Suzhou, Jiangsu 215123, People's Republic of China
| | - Haijun Zhang
- National Laboratory of Solid State Microstructure, School of Physics, Nanjing University, Nanjing, Jiangsu 210093, People's Republic of China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, Jiangsu 210093, People's Republic of China
| | - Yi Zhang
- National Laboratory of Solid State Microstructure, School of Physics, Nanjing University, Nanjing, Jiangsu 210093, People's Republic of China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, Jiangsu 210093, People's Republic of China
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Kastorp CFP, Duncan DA, Scheffler M, Thrower JD, Jørgensen AL, Hussain H, Lee TL, Hornekær L, Balog R. Growth and electronic properties of bi- and trilayer graphene on Ir(111). NANOSCALE 2020; 12:19776-19786. [PMID: 32966486 DOI: 10.1039/d0nr04788k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Interesting electronic properties arise in vertically stacked graphene sheets, some of which can be controlled by mutual orientation of the adjacent layers. In this study, we investigate the MBE grown multilayer graphene on Ir(111) by means of STM, LEED and XPS and we examine the influence of the substrate on the geometric and electronic properties of bilayer graphene by employing XSW and ARPES measurements. We find that the MBE method does not limit the growth to two graphene layers and that the wrinkles, which arise through extended carbon deposition, play a crucial role in the multilayer growth. We also find that the bilayer and trilayer graphene sheets have graphitic-like properties in terms of the separation between the two layers and their stacking. The presence of the iridium substrate imposes a periodic potential induced by the moiré pattern that was found to lead to the formation of replica bands and minigaps in bilayer graphene. From tight-binding fits to our ARPES data we find that band renormalization takes place in multilayer graphene due to a weaker coupling of the upper-most graphene layer to the iridium substrate.
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Affiliation(s)
- Claus F P Kastorp
- Department of Physics and Astronomy, Aarhus University, Aarhus, Denmark.
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Hell M, Ehlen N, Marini G, Falke Y, Senkovskiy BV, Herbig C, Teichert C, Jolie W, Michely T, Avila J, Santo GD, Torre DMDL, Petaccia L, Profeta G, Grüneis A. Massive and massless charge carriers in an epitaxially strained alkali metal quantum well on graphene. Nat Commun 2020; 11:1340. [PMID: 32165617 PMCID: PMC7067783 DOI: 10.1038/s41467-020-15130-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 02/21/2020] [Indexed: 11/23/2022] Open
Abstract
We show that Cs intercalated bilayer graphene acts as a substrate for the growth of a strained Cs film hosting quantum well states with high electronic quality. The Cs film grows in an fcc phase with a substantially reduced lattice constant of 4.9 Å corresponding to a compressive strain of 11% compared to bulk Cs. We investigate its electronic structure using angle-resolved photoemission spectroscopy and show the coexistence of massless Dirac and massive Schrödinger charge carriers in two dimensions. Analysis of the electronic self-energy of the massive charge carriers reveals the crystallographic direction in which a two-dimensional Fermi gas is realized. Our work introduces the growth of strained metal quantum wells on intercalated Dirac matter. Cesium atoms that are grown on intercalated bilayer graphene can create an ordered epitaxial film. Here, the authors report that such a strained film can host quantum well states with high electronic quality as characterized through angle-resolved photoemission spectroscopy.
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Affiliation(s)
- Martin Hell
- II. Physikalisches Institut, Universität zu Köln, Zülpicher Strasse 77, 50937, Köln, Germany.
| | - Niels Ehlen
- II. Physikalisches Institut, Universität zu Köln, Zülpicher Strasse 77, 50937, Köln, Germany.
| | - Giovanni Marini
- Department of Physical and Chemical Sciences and SPIN-CNR, University of L'Aquila, Via Vetoio 10, I-67100, Coppito, Italy
| | - Yannic Falke
- II. Physikalisches Institut, Universität zu Köln, Zülpicher Strasse 77, 50937, Köln, Germany
| | - Boris V Senkovskiy
- II. Physikalisches Institut, Universität zu Köln, Zülpicher Strasse 77, 50937, Köln, Germany
| | - Charlotte Herbig
- II. Physikalisches Institut, Universität zu Köln, Zülpicher Strasse 77, 50937, Köln, Germany
| | - Christian Teichert
- II. Physikalisches Institut, Universität zu Köln, Zülpicher Strasse 77, 50937, Köln, Germany.,Institute of Physics, Montanuniversität Leoben, Franz Josef Str. 18, 8700, Leoben, Austria
| | - Wouter Jolie
- II. Physikalisches Institut, Universität zu Köln, Zülpicher Strasse 77, 50937, Köln, Germany.,Institute for Molecules and Materials, Radboud University, AJ Nijmegen, Netherlands
| | - Thomas Michely
- II. Physikalisches Institut, Universität zu Köln, Zülpicher Strasse 77, 50937, Köln, Germany
| | - Jose Avila
- ANTARES Beamline, Synchrotron SOLEIL & Universite Paris-Saclay, L' Orme des Merisiers, Saint Aubin-BP 48, 91192, Gif sur Yvette Cedex, France
| | - Giovanni Di Santo
- Elettra Sincrotrone Trieste, Strada Statale 14 km 163.5, 34149, Trieste, Italy
| | - Diego M de la Torre
- II. Physikalisches Institut, Universität zu Köln, Zülpicher Strasse 77, 50937, Köln, Germany
| | - Luca Petaccia
- Elettra Sincrotrone Trieste, Strada Statale 14 km 163.5, 34149, Trieste, Italy
| | - Gianni Profeta
- Department of Physical and Chemical Sciences and SPIN-CNR, University of L'Aquila, Via Vetoio 10, I-67100, Coppito, Italy
| | - Alexander Grüneis
- II. Physikalisches Institut, Universität zu Köln, Zülpicher Strasse 77, 50937, Köln, Germany.
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